Objective To systematically review the effectiveness of letrozole combined with GnRH antagonist for in vitro fertilization-embryo transfer (IVF-ET) in poor responders. Methods Such databases as VIP, CNKI, PubMed, EMbase and FMJS were electronically searched for randomized controlled trials (RCTs) or quasi-RCTs on the effectiveness of letrozole combined with GnRH antagonist for IVF-ET. Two reviewers independently screened literature according to the inclusion and exclusion criteria, extracted data, and assessed methodological quality. Then, meta-analysis was performed using RevMan 5.0 software. Results Six studies involving 977 patients were finally included. The results of meta-analysis showed that, for IVF-ET poor responders, compared with the control group, the letrozole combined with GnRH antagonist group had less dosage of Gn (MD=–8.05, 95%CI –13.67 to –2.43, P=0.005), and lower serum E2 value on the day of HCG administration (MD= –1 026.41, 95%CI –1 949.61 to –103.20, P=0.03). However, no significant difference was found in the number of ocytes obtained (MD= –0.61, 95%CI –2.41 to –1.19, P=0.51) and clinical pregnancy rates (OR=1.03, 95%CI 0.53 to 2.02, P=0.92) between the two groups. Conclusion As for the effectiveness of impelling-ovulation treatment for IVF-ET in poor responders, letrozole combined with GnRH antagonist is similar to the control scheme in clinical outcomes, but it reduces the dosage of Gn and treatment costs of IVF-ET, which provides another clinical option for poor responders. Due to the limited quantity and quality of the included studies as well as the difference in methodology, we suggest this above conclusion could be taken as a reference for clinical analysis which needs to be further evaluated in its effects.